The present invention relates to a drive spindle, in particular to drive garage doors, having recesses or projections disposed on the circumferential surface which can be connected to corresponding projections or recesses of a guide element for the purpose of the axial movement of the drive spindle. Such drive spindles are widely used as machine elements to transform a rotary into a translatory movement, for example in feed drives or machine tools. For the driving of doors or gates such as garage doors, corresponding spindle drives are frequently used in place of chain or belt drives and unlike these have a relatively simple construction. Known spindle drives have the disadvantage that due to the in part substantial length of the drive spindle, the transportation to the place of assembly is difficult and complicated and that the storage of such drives requires a relatively large amount of space.
It is therefore the object of the present invention to provide a drive spindle which is easy to transport and to store.
This object is solved on the basis of a generic drive spindle in that the drive spindle consists of at least two components which can be detachably connected to each other. The individual components of the spindle advantageously possess a length which allows problem-free handling during transportation and space-saving storage. In this way, it is possible in accordance with the invention to transport and store without problems also long drive spindles which can be used to generate a correspondingly large adjustment movement. As a result, the size of the spindle drive dismantled into its component parts during transportation is not necessarily determined by the length of the drive spindle, butxe2x80x94for examplexe2x80x94by the size of the guide element or of any necessary retaining device. Before being put into operation, the components of the drive spindle are assembled in an easy manner and inserted into the guide element, whereby such an assembly of the spindle drive can also be performed easily by non-specialist persons. The engaging of the projections of the guide element or spindle in the recesses of the spindle or guide element effects the desired translatory motion of the drive spindle as it rotates.
In accordance with a preferred embodiment of the present invention, the drive spindle is designed as a screw spindle with a square thread, in particular a trapezoidal thread, or a round thread. In this case, a corresponding groove-shaped recess in which the thread flanks are guided is located in the guide element.
In another embodiment of the present invention, it is provided that the circumferential surface of the drive spindle has a thread-shaped recess which can be connected to an internal thread or a projection of the guide element. Here, too, a corresponding engagement results between the drive spindle and the guide element which, as the drive spindle rotates, effects a desired translatory motion which is required to open or close a garage door, for example. The guide element can be designed with an internal thread which engages the recess of the drive spindle. It is equally possible for the guide element to possess only one projection which engages the thread-shaped recess of the drive spindle. To reduce the friction between the guide element and the drive spindle, it is equally feasible for the projection to be designed not rigidly, but as a sphere or roll. The disadvantage of such a more complex manufacture is countered by the advantage that the friction and so also the wear can be reduced with such an embodiment.
In accordance with a preferred embodiment of the present invention, the drive spindle possesses a borehole with an axial direction into which a support element is at least partially insertable. The provision of such a support element simplifies the assembly of the drive spindle on the one hand, as these can be pushed onto the support element in a simple manner and then only have to be connected to one another. On the other hand, such a support element ensures the correct radial alignment of the spindle components which is required for a trouble-free function of the spindle drive.
The support element can consist of a rope, a rod or a pipe.
It is particularly advantageous if the support element is designed as a rod or a pipe, with the rod or pipe being made of at least two parts which can be detachably connected to one another. In this way, it is possible for the support element, which may possess a substantial length in the assembled state of the spindle drive, to be dismantled into parts which can be transported without any problem.
The parts of the rod or pipe can be connectable by means of a thread. The parts of the support element which are separated from one another during transportation or storage for space reasons can be screwed together without problem during assembly. Equally, any other suitable connection technique can be used. Here, it is meaningful that first the support elements are screwed together and then the components of the drive spindle placed thereon and then connected to one another.
It is particularly advantageous if, for the transmission of the translatory motion of the drive spindle, the support element can be connected to the component to be moved, in particular to a garage door. The support element thus serves, on the one hand, the simplification of the assembly of the components of the drive spindle. They are pushed onto the support element and thus already fixed in a suitable radial position. On the other hand, if the support element is correspondingly sized or with a corresponding number of parts forming the support element, it can be used to effect the desired axial motion of, for example, a door.
An effective connection formation between the components of the drive spindle can be achieved by the components possessing serrations on their front side by means of which these can be connected. In this way, a relatively simple detachment and connection of the components is possible.
It is particularly advantages if the serrations are formed as Hirth-type serrations.
In accordance with a preferred embodiment of the present invention, it is provided that the guide element can be accepted in a retaining device. The retaining device essentially serves to fix the spindle drive to, for example, a garage ceiling. When assembling a spindle drive having the drive spindle in accordance with the invention, first, for example, the retaining device is mounted, then the components of the drive spindle and the parts of the support element are connected to each other, the drive spindle inserted in the guide element and this arrangement is finally connected to the retaining device. It is equally feasible that the guide element is fixed to the retaining device prior to insertion of the drive spindle.
The retaining device can consist of a beam. A particularly simple connection results if the guide element can be pushed into the retaining device and subsequently fixed therein.
In accordance with a preferred embodiment of the invention, it is provided that the drive spindle and/or the support element and/or the guide element and/or the retaining device have or are made of plastic. The use of plastic offers weight advantages on the one hand and, on the other, by selecting the right plastic, a wide variety of different strengths and wear properties of the components. In addition, components made of plastic are relatively cheap and can be manufactured without problems with the required features such as projections, recesses or threads. It is also possible to combine different plastics together in a suitable manner.
In another embodiment of the present invention, it is provided that the retaining device is made of steel and the drive spindle, the support element and the guide element of plastic. The use of steel for the retaining device serves the particularly secure and loadable fixing of the whole spindle drive to a wall or ceiling. To keep the weight of the entire construction low while still ensuring perfect function, the drive spindle, the support element and the guide element are made up of plastic.